1. Field Of The Invention
The field of art to which this invention pertains includes a manually operable shift control mechanism and more particularly an escapement assembly for producing sequential single-step shifts of the transmission, with escapement override means also permitting rapid multi-step shifting if so desired.
2. Description Of The Prior Art
Co-pending application Ser. No. 731,391, of Robert W. Wolfe, filed Oct. 12, 1976, which is also assigned to the assignee of the present invention, discloses a novel shift control system for a multiple input transmission that is preferably used with the multiple input transmissions set forth in U.S. Pat. No. 4,000,662, issued Jan. 4, 1977. The transmissions set forth in said patent all have a multiple input portion and a multiple output portion, each of which in turn contains a plurality of constant-mesh change speed gears to provide for a plurality of drive ratios in response to movement of an operator's shift lever or the like.
The multiple use of the gears of this transmission requires a sophisticated shift control system, especially if this system is of the preselector or semi-automatic type wherein shifts between drive ratios are made in response to the movement of an operator's shift lever and the release of the torque on the drive train. Since the transmission is indirectly controlled by the shift control mechanism, it is preferred that the shift control mechanism afford the operator a distinct "feel" for each transmission setting. In addition, the shift control mechanism should provide the operator with means for readily obtaining the next transmission setting (either upshifting or downshifting) without difficulty and without requiring visual contact with the selector lever.
Examples of prior art patents which include control systems with escapement means include U.S. Pat. Nos. 3,874,248 to Hauser et al; 1,976,309 to Thomson; and 3,800,614 to Johnson.